AI Model Release Tracker - Timeline of Major AI Models from 2022-2026

Claude Sonnet 4.5 vs GPT-5.6 Terra

Anthropic
Claude Sonnet 4.5
OpenAI
GPT-5.6 Terra
Overview
CompanyAnthropicOpenAI
Release dateSep 29 2025Jun 26 2026
AccessProprietaryProprietary
Benchmarks
Nonsense detection
BullshitBench v2
79%
Coding
SWE-Bench Verified
77.2%
Science
GPQA Diamond
83.4%
Multimodal
MMMU
68%
Timeline
Release gapClaude Sonnet 4.5 shipped 270 days before GPT-5.6 Terra

Which is better: Claude Sonnet 4.5 or GPT-5.6 Terra?

Claude Sonnet 4.5 and GPT-5.6 Terra don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Claude Sonnet 4.5 shipped 270 days before GPT-5.6 Terra, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

Direct benchmark comparisons are unavailable — Claude Sonnet 4.5 and GPT-5.6 Terra don't publish scores on any of the same benchmarks.

Frequently asked questions

Claude Sonnet 4.5 was released by Anthropic on Sep 29 2025.

GPT-5.6 Terra was released by OpenAI on Jun 26 2026.

Other comparisons